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The impact of the land use landscape pattern on river hydrochemistry has significant scale effects. It is the premise and foundation of landscape optimization and the conservation of water resources to accurately identify the core scale of the landscape pattern impacting on river hydrochemistry. Taking Binggou River Basin in the source region of Shiyang River Basin as the study area, this paper selected the three spatial scales of catchment area, buffer zone, and riparian zone, and the relationships between land use types and landscape indices and river hydrochemical characteristics were analyzed at different spatio-temporal scales using redundancy analysis. The results showed that the hydrochemistry characteristics of Binggou River Basin had strong temporal variability, and the rainy season was the key period when the land use landscape pattern affected the river hydrochemistry. The sub-watershed and riparian scales were the core scales of influence of the landscape pattern on river hydrochemistry in Binggou River Basin. In particular, the landscape pattern index contributed the most to the river hydrochemistry at the sub-watershed scale on the whole, which was the core scale affecting river hydrochemistry. The “source” or “sink” functions of the same land use type also changed as the scale changed. Forest land showed weak “source” effect at the sub-watered scale, but a strong interception effect on the soil erosion process at the riparian scale, which is a typical “sink” landscape.

Based on the total carbon emission data of 30 provinces and cities in China from 2000 to 2020, this paper used non-parametric kernel density estimation and traditional and spatial Markov probability transfer matrix methods to explore the temporal and spatial dynamic evolution characteristics of carbon dioxide emissions in China and then used a super-SBM model to calculate the carbon emission reduction potential of each province. The results showed that: (1) from 2000 to 2020, the total carbon emissions in China showed an upward trend of fluctuation, from 1.35 Gt to 4.90 Gt year by year, with an annual growth rate of 13.10%. (2) The core density curve showed a double peak form of “main peak + right peak,” indicating that a polarization phenomenon occurred in the region. (3) The overall trend of carbon dioxide emissions shifting to superheavy carbon emissions was significant, and the probability of transition was as high as 74.69%, indicating that it was challenging to achieve leapfrog transition in the short term. (4) Based on the principle of fairness and efficiency of provincial carbon emission reduction, mainland China’s 30 provincial administrative regions can be divided into four types. Finally, the carbon emission reduction path is designed for each province.

This study sought to investigate the invasive mechanism of Myriophyllum aquaticum by subjecting it to simulation experiments in varying water temperatures ranging from 0 °C to 30 °C. The results showed that water temperature considerably affected both the growth and reproduction of M. aquaticum. The optimal temperature range for the growth of M. aquaticum was 25‒30 °C. Although the growth of M. aquaticum was inhibited at temperatures between 0‒5 °C, this did not result in mortality. The stem nodes, branches, and diameter reached maximum values over a temperature range of 20‒25 °C. High-temperature stress at 30 °C led to a gradual decrease or disappearance of branches. Compared to the 0 °C, 5 °C, and 30 °C treatment groups, a temperature of 20 °C led to biomass accumulation and significantly higher values. M. aquaticum’s physiological activities were affected by temperature. Except for 10 °C and 15 °C, the catalase activity varied among different water temperatures. M. aquaticum catalase activity was maximal at 5 °C and minimal at 25 °C. Conversely, the synthesis of photosynthetic pigments was highest at 10 °C and 15 °C. The plant’s optimal temperature for growth was between 20 °C and 25 °C. When the temperature was <10 °C, M. aquaticum adapted to the water temperature’s potential damage. This plant has a notable ability to tolerate various temperatures. [ABSTRACT FROM AUTHOR]